robinson



Feb. 7, 1956 E. A. ROBINSON METHOD OF MAKING A VALVED INFLATABLE ARTICLE Filed April 7, 1948 INVENTOR mm B T MM m w United States Patent METHOD OF MAKING A VALVED INFLATABLE ARTICLE Eli A. Robinson, Amsterdam, N. Y.

Application April 7, 1948,.SerialNo. 19,494

15 Claims. (Cl. 15485) The invention relates to a patch or a valve structure and the like and a method of producing the same. Usually patches are secured to a rubber article and valves for bladders are similarly secured to the'bladder by cementing the two together. In preparing the surface to which the patch or valve and the like is to be secured it is necessary to buff the contacting surface before the cement is applied in order to obtain a good and air tight bond or adhesion etween the parts. It also takes time to so boil the article, to spread the cement and to press the patch or valve into contact with the surface to which it is to be attached and bonded. Many times too, even if the best of care is exercised, there will be a leak between the cemented surfaces of the patch or valve and the structure to which it is attached.

The invention also relates to a new and novel method of making an inflatable article such as the bladder of a playball, the inner tube for a tire, a playball without a casing and the like.

It is an object of the invention to construct a new and novel patch, valve or the like having a iim or head of uncured or substantially uncured rubber or rubber like material.

Another object of the invention is to provide a new and novel method of securing a patch, valve or the like to the surface to which it is intended to be attached.

A still further object is to provide a new and. novel method of manufacturing an inflatable article.

Other objects of the invention will be more apparent from the following description when taken in connection with the accompanying drawing illustrating various forms of the invention in which:

Figure l is a cross section through a mold for making valves for an inflatable article such as the bladder of a playball in accordance with the method of the invention.

Figure 2 shows a valve in position preparatory to atfixing a valve to a sheet for a bladder or other inflatable article.

Figure 3 is a section through a valve finally attached to the sheet of the inflatable article.

Fig. 4 is a perspective view of a patch of the invention and made similarly to the valve structures of Figures 1 through 3.

Figure 5 is a section at reduced size through an inner tube having a valve secured thereto.

The molding press, shown in Figure 1 may comprise one or a plurality of molds each comprising in the form shown an upper portion and a lower portion 11 secured in any suitable way to plates 12 and 13 respectively. The molds contain a cavity or chamber 15 of the shape of the desired article, the molds shown being shaped to form a valve 16 having a surrounding flange 17. Any valve may be constructed in accordance with the method of the invention such as metal insert, plastic and like valves, the valve particularly shown being of the plastic type in which a'plasticv sealing. material is pro- "ice vided in a chamber in the valve and through which a needle is plunged in order to inflate the bladder.

A plug or chunk of uncured natural iubber, synthetic rubber or similar rubber like or vulcanizable material in excess of that required to fill the mold chamber 15 is placed within the mold chamber and the mold portions are brought together usually by movement of the upper plate 12 under pressure towards the lower plate. Pressure and heat is applied to the molds such as by passing steam through the passages 19 to provide the heat for rendering the uncured plug soft so'that it flows under the heat and pressure to fill the mold cavities. The plug of crude rubberlike material supplies suflicient uncured material so that as it flows there is an excess which squeezes out around the periphery of the valve structure and forms a rim or bead 20 around the periphery of the flange 17 on the valve. The molds are stopped in their pressing or closing movement so that they are separated far enough apart from each other and any surrounding heated struc ture so that the excess forming the peripherial rim or ring 20 remains substantially uncured. It does get some curing as a consequence of the proximity of the heat and such curing may be approximately ten per cent but best results are obtained if this rim has a minimum amount of curing. The space between molds should be suflicien't to permit free circulation of room air thereabout so that the peripherial mead or ring is subjected to a minimum of curing heat or is subjected to approximate normal atmospheric or room temperatures. In other words the peripheral ring is subjected to a temperature substantially less than that of the material in the mold. The molds are held closed sufficiently long to at least partially cure the valve although it preferably is completely cured, the period of curing normally being anywhere from one to three minutes depending upon the composition of the vulcanizable or rubber like material.

The molds are opened and the valves removed from the molds. sheet of the inflatable article. The valves may be stored a reasonable amount of time as long as several days without deterioration of the ability of the valve to be secured to a rubber like or vulcanizable sheet.

The valve with its flange having the uncured periphery connected therewith is placed upon the sheet 22 of rubber like or vulcanizable material to which it is to be secured whereupon pressure is applied to the sheet and the valve such as by placing them between plates 23 and 24. The sheet is formed by known methods and may be of any desired thickness. This pressure squeezes out and flattens the rim or bead 20 of uncured or partially cured rubber-like material into the form illustrated in Figure 3. Preferably the bladder sheet is uncured after which the bladder and valve are subjected to heat to cure the flattened out uncured periphery of the flange and the bladder sheet with the result that a firm air-tight bond is obtained between the valve and the sheet.

The sheet to which the valve is attached may be uncured or cured not in excess of about 50% in which case a firm bond is obtained between the valve and particularly the pressed out uncured rim thereof and the sheet without the use of any cement or other adhesive and without requiring buffing of the contacting surfaces. Three steps are thereby eliminated in thernanufacture of the inflatable article. If the sheet is cured then an adhesive or cement is needed between contacting surfaces in order to secure an air tight bond, however, it is not necessary to butt each of the contacting surfaces thereby eliminating two time consuming steps in the methods heretofore found necessary in order to obtain a good airtight bond between the sheet and the valve or its flange. A considerable saving in labor costs is elfected as wellas Such valves are ready to be applied to theeliminating defective assemblies from failure to sulficiently buff the surfaces.

With the valve attached to the bladder sheet the bladder may be completed by securing a second bladder sheet thereto which completes the same. The two bladder sheets may be secured together in any known manner. The securing of such second sheet to the valved sheet constitutes a completion of the inflatable article.

The same method may be used in making a patch 25 for sealing punctures in inner tubes, bladders and the like, the molds in such case being flat surfaces or substantially flat surfaces and when spaced from each other in molding or curing relation, the space therebetween forms the molded cavity. A plug of vulcanizable or rubberlike material is placed between the molds and having an excess amount so that the excess flows out between the molds and forms the peripheral rim 26 of uncured or semi-cured vulcanizable or rubber like material. This patch may then be secured and bonded to an inflatable article such as an inner tube, bladder, etc. by applying an adhesive or cement to the surfaces and the uncured rim is pressed out to obtain an air tight bond between the inflatable article and the patch. Such a patch does not require buffing of the surfaces in order to secure a good air-tight bond. It is apparent that a valve is in effect a patch carrying a valve structure.

The method of attaching a valve may be used in the manufacture of inner tubes as illustrated in Figure 5. The usual method of making inner tubes is to extrude a tube of rubberlike material, cut it to length, cure the tube, cement a valve thereto and then join and cement the ends of the tube. With the process of the invention herein, the tube 29 is extruded or uncured rubberlike or vulcanizable material; a valve 27 of the metallic insert type is molded having a flange 28 with an uncured or partially cured head around the periphery of the flange as in Figure 2 which valve is pressed to the uncured tubular sheet adjacent one end thereof as illustrated in Figure 5 and utilizing the same method described in connection with the bladder valve. The tubular sheet may then be cured after which the inflatable article may be completed by cementing the ends of the tube together. It is clear also that the ends of the tube may be joined together before curing of the tube and any method of securing the ends together may be used.

The inner tube, the bladder or the playball comprises an enclosing envelope or inflatable article which will retain air or gas therein when inflated through the valve. In the method of their manufacture the usual bufling step and the application of cement is dispensed with when the sheet, to which the valve is secured or the envelope is not fully cured and the buiflng step is dispensed with when the sheet or sheets are cured at the time of attaching the valve thereto. The steps therefore may be defined if desired as consisting of the steps enumerated and excluding the bufling and cementing steps in one method and excluding the bufling steps in the method utilizing a cured sheet or sheets.

This invention is presented to fill a need for improvements in a patch, value and inflatable article and method of manufacturing the patch, valve and inflatable article. It is understood that various modifications in structure, as Well as changes in mode of operation, assembly, and manner of use, may and often do occur to those skilled in the art, especially after benefltting from the teachings of an invention. Hence, it will be understood that this disclosure is illustrative of preferred means of embodying the invention in useful form by explaining the construction, operation and advantages thereof.

What is claimed is:

1. A method of making a patch in a mold having upper and lower mold members forming an enclosed mold cavity extending to the edge of the members and a large open space around the periphery of the mold comprising, providing a mass of vulcanizable material in quantity in substantial excess of the volume of the mold cavity such that the mold cavity is completely filled and the excess flows outside of the mold periphery around the entire periphery thereof and into the substantially heat free open space, pressing at least one mold member towards the other to a point where there is a material space between the mold members around the periphery for the excess to squeeze out therebetween and attached to the material in the mold to form a substantial uncured ring attached around the entire periphery of the patch, and heating the material by heating at least one mold member until the material between the mold members is at least partially vulcanized and the peripheral ring is substantially uncured.

2. A method of molding a patch as in claim 1 in which the patch is only partially cured.

3. A method of making a valve with a flange in a mold having upper and lower mold members forming an enclosed mold cavity and a large open space around the periphery of the mold comprising, providing a mass of vulcanizable material in quantity in substantial excess of the volume of the mold cavity such that the mold cavity is completely filled and the excess flows outside of the mold periphery around the entire periphery thereof and into the substantially heat free open space, pressing at least one mold member towards the other to a point where there is a space between the mold members at the periphery for the excess to squeeze out therebetween and attached to the material in the mold to form a substantial uncured attached ring around the entire periphery of the flange, and heating the material by heating at least one mold member until the material between the mold memhers is at least partially vulcanized.

4. A method of making a valve as in claim 3 in which the valve is only partially cured.

5. A method of making a valved inflatable article using a mold comprising molding a separate valve of vulcanizable material having a surrounding molded flange, utilizing an excess of material so that the excess material flows outside of the mold and remains connected with and substantially uncured as a ring around the periphery of the valve flange, forming a sheet of vulcanizable material, pressing the molded valve flange and its peripheral ring against the sheet to flatten out the ring, and heating the valve flange and the sheet in contact with the valve flange to secure adhesion between the sheet and valve flange and its peripheral ring, and thereafter completing the inflatable article.

6. A method as in claim 5 in which the sheet of the inflatable article is no more than partially cured material, and thereafter curing the article.

7. A method as in claim 5 in which the sheet of the inflatable article is cured vulcanizable material, and including spreading an adhesive between the contacting surfaces of the sheet and valve flange.

8. A method as in claim 5 in which the valve is partially cured in the molding thereof, and the sheet of the inflatable article is no more than partially cured, and then completing the curing of the inflatable article.

9. A method of making an inflatable bladder comprising molding a separate valve of vulcanizable material having a surrounding flange, utilizing an excess of material so that the excess flows outside of the mold and remains substantially uncured around the periphery of the valve flange, forming a bladder sheet of vulcanizable material, pressing the valve flange and its periphery against the bladder sheet to flatten out the periphery and secure adhcsion between the sheet and the valve flange and its periphery, and securing a second bladder sheet to the valved sheet.

10. A method as in claim 9 in which the bladder sheets are no more than partially cured material and thereafter curing the bladder.

11. A method as in claim 9 in which the sheet of the bladder is cured vulcanizable material, and including spreading an adhesive between the contacting surfaces of the sheet or valve.

12. A method as in claim 9 in which the valve is partially cured in the molding thereof, and the sheet of the bladder is no more than partially cured, and then completing the curing of the bladder and valve.

13. A method of making a patch in a mold having upper and lower mold members forming an enclosed mold cavity extending to the edge of the members and a large open space around the periphery of the mold comprising, providing a mass of vulcanizable material in quantity in substantial excess of the volume of the mold cavity, pressing at least one mold member towards the other, stopping the pressing movement at a point where there is a material space between the mold members around the periphery for the excess to squeeze out therebetween forming a peripheral ring attached to the vulcanizable material in the mold around the entire periphery of the patch, subjecting the peripheral ring to approximate normal atmospheric temperatures whereby it is substantially uncured, and heating the material between the mold members until it is at least partially vulcanized.

14. A method of making a valve with a flange in a mold having upper and lower mold members forming an enclosed valve mold cavity with a central mandrel and flange portion and a large open space around the periphery of the mold comprising, providing a mass of vulcanizable material in quantity in substantially excess of the volume of the mold cavity, pressing at least one mold member towards the other, stopping the pressing movement at a point where there is a space between the mold members at the periphery of the flange portion for the excess to squeeze out therebetween forming a peripheral ring attached to the material in the mold around the en'- tire periphery of the flange, heating the material within the mold members for a period of time to at least partially vulcanize the same, and subjecting the peripheral ring to a temperature substantially less than that of the material within the mold.

15. A method of making an inflatable article with a valve having a flange in which the valve is made in a mold having upper and lower mold members forming an enclosed valve mold cavity with a central mandrel and a large open space around the periphery of the mold comprising, providing a mass of vulcanizable material in quantity in substantial excess of the volume of the mold cavity, pressing at least one mold member towards the other, stopping the pressing movement at a point where there is a material space between the mold members at the periphery of the flange portion for the excess to squeeze out therebetween forming a peripheral ring attached to the material in the mold around the entire periphery of the flange, heating the material within the mold members for a period of time to at least partially vulcanize the same, subjecting the peripheral ring to a temperature substantially less than that of the material within the mold, forming a sheet of vulcanizable material, pressing the molded valve flange and its substantially uncured periphery against the sheet to flatten out the periphery, heating the valve flange and the sheet which is in contact with the valve flange to secure adhesion between the sheet and valve flange, and thereafter completing the inflatable article.

References Cited in the file of this patent UNITED STATES PATENTS 1,569,689 Vannoni Jan. 12, 1926 1,612,575 Goldthread Dec. 28, 1926 1,628,821 Callahan et al May 17, 1927 1,638,659 Fairchild Aug. 9, 1927 1,653,162 Forman Dec. 20, 1927 1,866,628 Denmire July 12, 1932 1,895,738 Shugg et al. Ian. 31, 1933 2,012,935 Smith et al. Aug. 27, 1935 2,148,079 Martin, Jr. Feb. 21, 1939 2,195,424 Raiche Apr. 2, 1940 2,230,879 Bronson Feb. 4, 1941 2,275,081 Maynard Mar. 3, 1942 2,329,346 Goff Sept. 14, 1943 2,332,621 Brunner Oct. 26, 1943 2,363,508 Doster et al. Nov. 8, 1944 2,378,384 Baker June 19, 1945 

5. A METHOD OF MAKING A VALVED INFLATABLE ARTICLE USING A MOLD COMPRISING MOLDING A SEPARATE VALVE OF VULCANIZABLE MATERIAL HAVING A SURROUNDING MOLDED FLANGE, UTILIZING AN EXCESS OF MATERIAL SO THAT THE EXCESS MATERIAL FLOWS OUTSIDE OF THE MOLD AND REMAINS CONNECTED WITH AND SUBSTANTIALLY UNCURED AS A RING AROUND THE PERIPHERY OF THE VALVE FLANGE, FORMING A SHEET OF VULCANIZABLE MATERIAL, PRESSING THE MOLDED VALVE FLANGE AND ITS PERIPHERAL RING AGAINST THE SHEET TO FLATTEN OUT THE RING, AND HEATING THE VALVE FLANGE AND THE SHEET IN CONTACT WITH THE VALVE FLANGE TO SECURE ADHESION BETWEEN THE SHEET AND VALVE FLANGE AND ITS PERIPHERAL RING, AND THEREAFTER COMPLETING THE INFLATABLE ARTICLE. 